Writing instrument



FIG. 1 is a side perspective view of a writing instrument showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a back elevational view thereof;

FIG. 4 is a front elevational view thereof with the cap removed and placed on the rear in a stored position;

FIG. 5 is a right side elevational view thereof with the barrel in an open position, shown without the cap for convenience of illustration;

FIG. 6 is a top plan view of FIG. 1; and,

FIG. 7 is a bottom plan view thereof.

All portions shown in broken lines are environmental and illustrative only and form no part of the claimed design. 

The ornamental design for a writing instrument, as shown and described. 